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Lincoln Road Interchange Upgrade

By Matt L, on March 15th, 2011

When thinking about the Western Ring Route the most common thought is about completing the Waterview Connection however there is also another bit part of overall project and that is widening SH16 from St Lukes all the way through to Westgate. The image below shows the planned number of lanes for this entire section.

The works from Te Atatu to St Lukes are included as part of the Waterview Connection but the other parts aren’t and recently the NZTA started construction on the Lincoln Road interchange. I think most people that have used it would probably agree that Lincoln Rd has to be one of the worst interchanges on the Auckland motorway network. The on and off ramps are generally quite tight an curvy with little space to merge, the overbridge is narrow and you would have to be pretty brave to try getting across on foot.

So here is what the NZTA have said about it.

$100 million seems like a hell of a lot of money for one interchange and a small stretch of motorway on each side. So what are we going to get for that $100 million? The most promenant thing is that they are going to widen the bridge from 2 lanes to 7. The bridge is almost exclusively for access to and from the motorway and most of that is to get to the citybound onramp so why on earth does it need 7 lanes and what are they going to do with them all?

Of the other things we will get, more bus shoulders are better than what we have now but it seems like such a wasted opportunity not to have put a proper busway in as it serves a completely different catchment to the western rail line. They will realign the ramps and probably the best thing of the project is the cycleway will be extended a further 2km. So what is the interchange going to look like and what are all those lanes for? The NZTA don’t seem to have anything in the way of maps or diagrams online but I have managed to find the NOR documents that were filed with the old Waitakere City Council. There are quite a few maps as the project actually extends from just east of the Henderson Creek to Huruhuru Rd but here is the one for the interchange itself.

So we can see that there will be three lanes heading north towards the citybound onramp and one of those is a bus /HOV lane which seems reasonable, the transport assessment indicates that there won’t be huge numbers of buses even at peak time so this should be ok. We can also see that the 4 lanes that make up the rest of the bridge are all Southbound which seems completely overkill, even though one is a turning lane. You can also see some quite big changes to 3 of the 4 ramps, removing the tight corners that currently exist.

You can also see they have highlighted all of the footpaths/cycleways in yellow which makes them much easier to see. This is definitely a lot more than there are now however I can see one big issue with this, for someone travelling along the cycleway they will have to cross 4 sets of traffic lights just to be able to carry on their journey. How much more expensive would it have been to put a bridge in while they were doing all of these works, by doing it at the same time it and being for pedestrians/cyclists only it surely wouldn’t cost that much. A bridge also wouldn’t look that out of place as the area is light industrial and the nearest houses are 150-200m away. If a bridge was to much, what about a simple underpass? again if done at the same time it shouldn’t end up costing that much more. To me it just seems like the NZTA put it in the to hard basket which is a real shame as the NW cycleway is probably the best infrastructure of its kind in the city and many of the other onramps or major roads have been bridged over to allow a continuous journey.

Lastly you can also see the existing red dotted line marking the existing motorway boundary. With the realigned ramps, particularly the Eastbound ones, I wonder if the NZTA have considered selling off the excess land after they finish as there seems like there will be quite a bit available which could be redeveloped.

28 comments to Lincoln Road Interchange Upgrade

Would someone please explain why clover-leaf designs are no longer suitable? Is it hard to put in multiple lanes or are there lots of accidents? The eastbound cloverleaf looks like going the way of the dodo, like the one in Manukau (I’m not saying this is good or bad, just wondering).

It would also be interesting to know how many heavy trucks use that bridge and whether that had much influence on the design – the waste transfer station is just down the road and the concourse seems to carry a good amount of industrial traffic.

From having a skim through some of the reports it seems like the issue is safety related. If you are coming off that eastbound offramp you have to brake quite hard to be able to safely get around the corner and if you brake earlier you hold up other traffic. I have also encountered a car heading the wrong way on that ramp which I couldn’t see until I was half the way around, they then realised their mistake and did a U turn on the ramp, had someone else been coming off there it would have resulted in a crash. I also find that clover on ramp at Te Atatu means you often enter the motorway at a much lower speed to existing traffic.

Yes I imagine that there is quite a few truck heading down The Concourse, have a look at the traffic assessment on that NOR page, it has a lot of information about traffic flows through there. I do think that most of those trucks will be during the day however and not at peak so probably not taking up to much road space.

I think the clincher is simply that to get loops large enough to meet safe and efficient curvature standards, they end up being massive. So I suppose it’s fine on the plains of the American midwest where you can have ramps a half mile in diameter, but a bit tricky to do the same in suburban Auckland.

This is pretty much the current standard North American freeway design for a full movement diamond interchange in an urban area, and is being used extensively in currently ongoing reconstructions of Hwy 1 through Vancouver and I-405 in Seattle, to name a couple that I am familiar with. The large amount of traffic lanes are basically there to stack vehicles waiting at the traffic lights, in a manner that will allow complete discharge of waiting vehicles at each green light phase. However this becomes a bit of a vicious circle – the wider the road (i.e more traffic lanes) that you have the more likely you are to need a given intersection controlled by traffic signals, and the more signals you have, (and the closer together they are) the more lanes you need for stacking. It also becomes more hostile for anyone who is not in a motor vehicle, and uses a bit of land, though not as much as most other interchanges that will cope with a similar amount of expected traffic.

Josh – I agree that it is pretty messy for pedestrians and cyclists – this is one of the major issues with this type of interchange. It would be good to have as many grade separated movements as possible for non-motorised traffic. Ideally best practice here would be to have one North-South, and one East-West grade separated facility, and some link between the two. The North to South would be probably best addressed with a subway underneath Lincoln Road (maybe even under one end of the Motorway bridge, and E to W across SH16 with a separate nearby dedicated bridge that ideally continues over most or all of the off/on ramps.

Rob – cloverleafs were the standard during large scale interstate construction in the 1950’s in North America, but they have a number of safety issues, mostly around the on and off ramps being too close together which causes a lot of weaving – leading to accidents and increased congestion on the motorway mainline. This is mainly only a problem with full cloverleaf interchanges – of which I believe there are none existing in NZ. Partial cloverleafs (such as slightly more recent type of design known as a Parclo A4) can avoid this issue, but still not best practice as they take up a lot of land (think of all the unusable space inside the single cloverleaf at the junction of SH16 and Great North Road). The onramp cloverleafs also need to be quite large so vehicles, particularly trucks, can get up to the motorway speed before they merge, taking up even more land. They generally also are a bad type of design for cyclists and pedestrians, as average vehicle speeds tend to be higher, due to vehicles being able to free flow off the motorway into the urban arterial with their speed only limited by the curvature of the cloverleaf. A diamond interchange generally brings most traffic coming off a motorway to a halt or close to it – which mentally gets drivers out of high speed “freeway mode” and into 50km/h “urban” mode – a better road design that lowers vehicle speeds without requiring enforcement.

My thought was that surely it would have been better to put an underpass in under the westbound offramp, carry the cycleway alongside the motorway and under the new bridge (which would likely only have needed to be widened an extra few metres) carry it along through another underpass under the westbound onramp. Those wanting to get off the cycleway at Lincoln Rd could still do so and those carrying on further along SH16 wouldn’t have any issues.

Whoops, sorry Matt, I’ll check the byline before I comment next time. I wonder if the NZTA might end up going for a longer single subway underneath Lincoln Rd just to the west of the interchange, looking at the way Lincoln Rd is built up to go over SH16 this may be an easier option than tunneling under two ramps. Hopefully they do something for cyclists anyway…

From someone who cycles the NW this is “one of” the worst bits because of the high delay. It would be nice if they could have cyclist and pedestrian delays in mind when designing the interchanges. When there are multiple crossing points its even worse, for example it can take up to 3 phases for a cyclist to get through the St Lucks interchange.

I get that long cycle times apparently increase throughput, but if the interchange is blocked up why not reduce the cycle times to reduce ped and cycle delays.

A cycle and pedestrian link needs to be direct. Following the roads is ridiculous. Road interchanges can be many kilometers across, which can take half an hour to walk across. Traffic lights are frustrating enough in a car, it is ridiculous that a cyclist or pedestrian should have to stop at them.

Lets get some money spent on mini motorways for bicyclists and pedestrians built throughout the city.

Thanks Matt for writing this post – I don’t know whether you were aware of this, but your comments dovetail almost exactly with the comments made by us (Cycle Action Auckland) in our submission on the Notice of Requirement. We have also had discussion with NZTA engineers recommending exactly what you suggested – i.e. an ovebridge, preferably in the short section of Lincoln Road between the motorway and Central Park Drive / Triangle Road. This would likely look like the bridge over Great North Road in Pt Chevalier, i.e. an u-shaped arrangement.

We will keep pushing for such grade separation, for both safety and convenience reason – just as we have pushed for it during the Board of Inquiry process on Waterview for the Te Atatu interchange. We can’t just add obstructions to the cycleway just because we need to push more traffic on and off the motorway.

That said, NZTA have been positive and useful in their discussions with us – but as always, nothing’s confirmed until it’s confirmed, so we are very happy to see others like you highlight this!

No I wasn’t aware your submission, I just went looking for information on what was actually happening after all I heard was that it was costing $100m and the bridge would be 7 lanes wide. I’m not a cyclist but when I saw the amount of lights to negotiate this I just thought it was madness. Good to hear that the NZTA is having discussions with you on it.

Well, I can definitely say that if that goes through I’ll still be getting off at Central Park Dr and using the road as it’ll be a shedload quicker than waiting for 3-4 sets of lights to let me through. Te Atatu is bad enough at the moment. This looks worse.

As for the cycleway – which I would use from Westgate were there one there – I don’t think it would be a disaster if a high quality cycleway tracked along Lincoln road to the intersection with Central Park Drive, then down CPD to the current path near Tory Street. Only 1 crossing of a very busy road and CPD should be able to handle it comfortably.

What I want to know is “where is the full busway?” NZTA wriggled their way out of providing anything more than useless shoulder lanes as part of the Waterview Connection project because the Lincoln Road to Pt Chevalier section of SH16 is only a QTN rather than an RTN.

Well, SH16 between Lincoln and Westgate is an RTN. So where’s the busway NZTA?

Matt L – the bridge itself is under construction. The works around the bridge are not fixed yet, that’s what their last NoR was for. where people could submit – though of course the works will be heavily influenced by the bridge, so in some ways it is fixed, but not in all elements…

Interesting to hear the comments about cycling on CPD – I too thought that no cyclist would want to use four sets of lights at the interchange when they can just cross at Central Park Drive at one light. I hope NZTA fixes this with a bridge solution, of the shiny new cycleway might see less use here than it could.

It is all good adding more lanes to the bridge and motorway, but what about Lincoln Road itself? is this still three lanes off into two? With congestion both morning and night (even weekends)from the motorway upto Pak N Save.

Good question Rose! anyone got an answer. I have been trying to figure out what the changes to the bridge is for and looked at the western ring animated view on the NZTA following it all the way so I could see what the Lincoln interchange would look like only to find it stops at Te Atatu…..waste of time. This is where I found the above proposed plan which probably looks like it will be just as much of a night mare as the Lincoln and triangle road lights are every weekday morning. If what Rose is saying is true whats the point …..ohh of course you will be able to cram 50 extra cars onto the bridge. It will be obsolete by the time it is finished with further housing construction out west so we can get the rest of NZ into the narrowest part of the country.
Couldn’t agree with the cycle guys more and the real purpose of doing cycle ways is not just for pleasure cycling but to get people out of their cars and into good ol exercise to work. IF the cycle way was more accessible then I’d ride instead of stop start to work from Massey to Western Springs. We have the motorway closures to bear as well so they can do all this, yipes.

There isn’t really a need to put more lanes in along Lincoln Rd as it already has two each way (I don’t know where Rose thinks there are three lanes except for around the intersections) and adding extra lanes to Lincoln Rd wouldn’t have much benefit. What this project will do is just get more people to the motorway onramps faster and the NZTA have already admitted that all they are really doing is shifting the congestion from the local roads onto the motorway which of course that helps them to justify some of the widening they are doing.

So they are re-introducing the Southbound off ramp – which they should never have closed in the first place….. I made a submission at the time….. It seems to me that the right turn from Lincoln Road heading towards the city will be far too tight for large trucks……..

The eastbound off ramp originally exited onto the western side so the interchange was a proper diamond then some years ago it was changed to its current configuration which I assume was due to the ramp being too short and therefore a bit dangerous. The documents indicate that new bridges will be built over the creek which will provide enough safe distance to return the interchange to a diamond.

I dont know why Auckland Council, as part of its Light rail program, put in a Monorail down the length of the Northwestern motorway, using all the land areas (westgate, Lincoln rd and te Atatu) as park and ride areas. Monorail is totally futureproof, not subject to traffic delays and probably cheaper than the bus lanes. Once installed, it is just a matter of maintenance and incressing frequency to cope with influx. If you are interested, have a look at this link:http://www.hitachi-rail.com/products/monorail_system/overview/index.html

The job is looking great so far .the problem is when its marked up with road marking and cycle way markings are they going to use that Glass system which is failing across Auckland .Its a costly experience .The contractors who put this stuff down know its fails and they also kniow there is a group in Auckland who make a far better product .the big question is do they care they are taking money for us the rate payers to cover a system that fails and contains lead